What would your interpretation of this UOA be then:
Just a quick look, my guess for higher metals would be mainly corrosion, esp. the iron.
Read through the rest of the thread
Read through the rest of the thread
For reference, the OP in that thread is Doug Hillary, who wrote the article on UOA's featured on the main page of this site and has millions (probably 10's of millions) of kilometres of UOA experience spanning a huge array of equipment
He's not at all concerned about the numbers and considers them "normal".
OK, understood, I can see his POV in that example. I have a different opinion, and my idea of break-in/run is also different. I have found a few more discussions with him cited, who obviously has a vast store of experience that I don't have, which I am going to read up on more.
Yes, he (@Doug Hillary ) is a wealth of knowledge on UOA's, likely having more experience with them than everyone else on here combined. Very much an SME on the topic.
I saw that, and largely discounted it as a reason since AL was constant, unless dirt got in during one of the many top-ups. Again, this report shows to me something worth investigating further, not running it as is until doing so, esp. since money was spent to freshen the head. This is a loose engine, if healthy these should be low numbers overall with near zero bearing metals. If a one time event, the bearing metals at 370 should largely be gone now. I believe the problem, whatever it is, persists but just not as acutely as at 370. It could be something as simple as a tired oil pump or loose drainback or pressure valve that allows dry (or almost dry) starts. But, I will bet money those bottom end bearings are ready to be replaced. Since the OP freshened the head, it makes sense to look at the block now as well.
Definitely a possibility, I certainly wouldn't discount it being from contamination, I think the silicon is a tell.
Remember though, we are talking parts per million, bearing metals are low. What we did briefly see spike was silicon, followed by a small uptick in bearing metals.
I disagree, it depends on the size of streak and how long it took to smooth out.
Well, this, and some inference of bearing health, can be gleaned from oil pressure readings. I wonder if he has a gauge?
I don't think anybody is arguing they are mint at this level of mileage, but I'm also not willing to condemn them as being worn out. The levels we are seeing are quite low, and did appear to be trending down after the 370K high silicon interval. If we had oil pressure, it would give us some more insight into the condition of the bottom end.
You need a re-calibration. Condemnation limits are usually in the hundreds of parts per million.
Well, we differ, and that's OK. Not the first time, right?
My point, which I do not think is unreasonable at all, is to take a look in the bottom end of that engine. If the bearing metal was not present in such quantity in the current and previous UOA, I would take the view that it's fine and run it. But that is not the case. It would likely take under an hour to drop the pan in that car, less man-hours than we have all spent reading and responding to this thread. Also, I'm almost 100% sure that the oil pan was sealed with Hondabond in '94, and it could use a freshening at the very least!Spoken with such authority! I'm sure the engine will stay together long enough to conveniently give you that UOA.
Failed parts end up in the oil pan. I am willing to bet the oil filter and previous drains also show larger particles that are not in the UOA. But again, I don't know why it's controversial to drop the pan and know for sure, esp at this mileage. It's a quick job.
I really can't recall another time that someone around here had suggested a bottom end rebuild based solely on a UOA. The only reason I'd take an engine apart based on an UOA is if it was indicating coolant in the oil.
I wouldn't call it numerous. I've found a little oil around the factory oil vapor box area, where the PCV valve lives. I have some replacement hoses and fittings to install, as soon as I have time to get access to the area. There also may be a bit leaking from the oil cooler sandwich plate at the filter, and possibly a little from the oil pan. Oil pan gasket is a Fel-Pro, but I may try something different soon.
Always using M1 0w30. I may have used a quart of the ESP flavor once this last time, by mistake, instead of the normal AFE version.
yep that's in the plans, but probably not for another 1-2 years down the road.
I had the head surfaced, and the valve seals replaced. Not exactly what I would call a "rebuilt head". It's still using all the original valves, springs, camshafts, rocker arms, cam caps and everything else in there.Although I agree with you, a loose (old) engine will produce more metal vs when everything was tight and new because the parts now have some play in them and this aids in wear as things vibrate.
Also, the OP stated this is the original drivetrain at 381k miles (never rebuilt) at the top of his post but then proceeds to tell us a story about how he rebuilt the head at 330k when the head gasket blew.
Ummm… that’s not how it works.
